I wonder if Denmark ditching Microsoft is directly related to Schleswig-Holstein doing it. Specially given they’re neighbours.

It's not, but our direct neighbors announcing it first surely helped the people lobbying to get it considered. It's also not the entire Government, just a small portion of it. Some municipalities have already been using Linux on user-facing computers like in libraries and I'm sure on the inside, as well.

The discussion is up because of the current American administration, and would continue to be up regardless of if Schleswig-Holstein or anyone else announcing their intentions to do the same.

These companies hate PCs because of the flexibility and choice. Thus Chromebooks, et al. Lock that stuff down and channel any installs through a single point of control, and do it by convincing anyone who needs a secure application that they don't need to work too hard at it, the closed system will protect them.